This invention relates in general to orthodontic appliances and more particularly to orthodontic brackets.
In orthodontics it is common practice to reposition a malpositioned tooth by applying a force to that tooth through an arch wire which generally follows the arch defined by the row of teeth in which the malpositioned tooth is located. The arch wire is normally connected with the teeth by bands which fit around the individual teeth and brackets which are secured to the bands and engaged with the arch wire. The correctly positioned teeth merely serve as anchors for the arch wire which exerts forces on the malpositioned teeth to move those teeth into correct positions.
As to each malpositioned tooth, the shape of the bracket for that tooth, its location on the band around the tooth, and the configuration of the arch wire at the bracket are all critical to repositioning the tooth. As a consequence, the brackets are supplied in many different configurations. For example, the basic configuration is referred to as a "single" which is merely a relatively narrow projection from the band. Next, is a "double" which like the single is a single projection from the band, only it is about twice as wide as the single. Then there are "narrow twin," "medium twin," and "wide twin" brackets, each of which has two projections from a common base that is secured to a band. The spacing between the projections is less for the narrow twin than for the wide twin as the names imply.
The wide variety of brackets needed for orthodontic work requires the orthodontist to maintain a large supply of such brackets. Moreover, orthodontic treatment relies on gradual migration of teeth to their proper positions upon the application of correctly oriented forces, and by its very nature requires repeated visits to the orthodontist at closely spaced intervals, often as short as a week or two. These visits give the orthodontist an opportunity to inspect the migration of the malpositioned teeth and to further make adjustments in the orthodontic appliances. These adjustments often involve converting from one configuration of bracket to another or changing the position of a bracket on its band. This requires complete removal of the band from the tooth so that the new or repositioned bracket can be welded to the band at the proper location.